The Sunday Times's leakage of the government's "Yellowhammer" dossier certainly seems to have set the cat amongst the pigeons – which perhaps was the intention.

Predictably, the media are piling in, which is hardly surprising given a slow news day at the fag end of the silly season. There's hardly an outfit in the country (or world, even) which could pass up on such a juicy story.

Equally predictable was the response of No 10, which is apparently "furious" at the leak, although they would convey that view, come what may. In all probability though, that fury is genuine – it has that feel about it. The Johnson administration didn't want this.

The Guardian has Downing Street putting the timing down to a determination of a hostile former minister to spike the trips the prime minister in office intends to make in the coming week to see the two "M"s, Merkel and Macron.

However, the timing is probably a coincidence, as the leak probably pre-dates the public announcements of Johnson's visits and anyone with inside knowledge would doubtless not bother trying to sabotage them. Seeing Merkel and Macron was exactly what Mrs May did and it was a complete waste of time.

If Johnson has a purpose at all, it must be purely cosmetic, as no one serious could believe that even these two pre-eminent heads of state can achieve anything on Brexit outside the formal context of the European Council.

As for dealing with the fallout of the leak, the brunt of the rebuttal effort was borne yesterday by Michael Gove, the minister in charge of Brexit preparations, who has been insisting that the dossier was an "old document" that did not reflect significant steps taken by Johnson’s administration over the last four weeks. He also argues that the dossier shows "the worst-case scenario".

This, from a reading of the document, is actually a given, with Gove promising that "very significant steps" had been taken in the last three weeks to accelerate Brexit planning. And together with the action taken by Continental authorities, it is hard to dispute that measures have been taken to mitigate the worst effects of Brexit.

Nevertheless, the leak has been a godsend for the considerable constituency who want to believe the worst, and soonest. There are no nuances here. Those who want to see Brexit fail will take anything they can get and make the most of it.

One of those is the former head of the civil service, Lord Kerslake. Despite its obvious flaws, he describes the dossier as "credible", claiming that it "lays bare the scale of the risks we are facing with a no-deal Brexit in almost every area". In his view, the risks "are completely insane for this country to be taking and we have to explore every avenue to avoid them".

One of the projected outcomes of the "Yellowhammer" dossier is a hard border between Northern Ireland and the Republic. Although HMG intends to activate the "no new checks with limited exceptions", the dossier argues that this model "is likely to prove unsustainable because of economic, legal and biosecurity risks".

With the UK becoming a third [non-EU] country, the automatic application of EU tariffs and regulatory requirements for goods entering Ireland will severely disrupt trade. The expectation is that some businesses will stop trading or relocate to avoid either paying tariffs that will make them uncompetitive or trading illegally.

Others will continue to trade but will experience higher costs that may be passed on to consumers. The agri-food sector will be hardest hit, given its reliance on complicated cross-border supply chains and the high tariff and non-tariff barriers to trade.

In terms of detail, "Yellowhammer" suggests that disruption to key sectors and job losses are likely to result in protests and direct action with road blockades. Price and other differentials are likely to lead to the growth of the illegitimate economy.

This, we are told, will be particularly severe in border communities where criminal and dissident groups already operate with greater freedom. Given the tariff and non-tariff barriers to trade, there will be pressure to agree new arrangements to supersede the Day 1 model within days or weeks.

This brings Irish Deputy Prime Minister Simon Coveney into the fray, tweeting that Dublin had "always been clear" a hard border in Ireland "must be avoided". On the other hand, Michelle O'Neill, Sinn Fein's deputy leader, accused Johnson of treating the Northern Ireland peace process as a "commodity" in Brexit negotiations. She said Ireland as a whole had been voicing concerns about a no-deal Brexit for months.

Scottish MPs weren't silent either. SNP's Stephen Gethins pitched in to say that the dossier laid bare the "sheer havoc Scotland and the UK are hurtling towards". And back home, Lib-Dem MP Tom Brake said it showed the effects of a no-deal Brexit should be taken more seriously. "The government", he says, "has simply, I think, pretended that this wasn't an issue", arguing that the dossier revealed "the truth" that no-deal would "have wartime implications, in peacetime, all of them self-inflicted".

This brings in the US dimension where Brake is saying that ministers are in "a real pickle" since the "the US has said that if that border is jeopardised, we're not going to get a trade deal with them". This alludes to US House of Representatives Nancy Pelosi who said on Wednesday that a US-UK trade deal would not get through Congress if Brexit undermined the Good Friday Agreement.

The Freight Transport Association (FTA) also reacted with alarm to the idea of fuel shortages in particular, saying these possibilities had not been conveyed to them by the government.

"This", a spokeswoman says, "is the first time the industry is learning of any threat to fuel supplies – a particularly worrying situation, as this would affect the movement of goods across the country, not just to and from Europe, and could put jobs at risk throughout the sector which keeps Britain trading".

"Yellowhammer" says that, because of the imposition of checks at its border with Spain (and the knock-on effect of delays from the UK to the EU), Gibraltar will see disruption to the supply of goods (including food and medicines) and to shipments of waste, plus delays of four-plus hours for at least a few months in the movement of frontier workers, residents and tourists across the border.

It also suggests that prolonged border delays over the longer term are likely to harm Gibraltar's economy, noting that - as on the UK mainland - cross-border services and data flow will be disrupted.

Yet, a dusty response from the government of Gibraltar states that the reports in the Sunday Times as they applied to Gibraltar were "out of date and were based on planning for worst case scenarios which the Government of Gibraltar has already dealt with".

According to this statement, the government of Gibraltar has been working closely with the UK on Yellowhammer "for many months". They have already commissioned all necessary works at the port in Gibraltar in order to have even further contingency capacity in maritime traffic.

Thus does the Chief Minister of Gibraltar, the Hon Fabian Picardo QC MP, say "We do not want a no-deal Brexit. We think it is bad for Gibraltar. We are, nonetheless, now ready for it. The matters raised in the outdated Yellow Hammer leak have already been responsibly addressed in detail".

Now, while Johnson, himself is blaming former ministers, his administration is being urged to bring forward the planned no-deal campaign in order to counter what is now being termed as "scaremongering".

In that context, ministers are described as being "forced onto the backfoot" by "Yellowhammer" , an additional indication that there is a sabotage effort in progress. But, with the fight-back in progress, the leak may now be seen as rather counterproductive.

The thing is that we may well be facing considerable disruption, but not on the timescale and of the nature suggested by "Yellowhammer". The leakers may have been crying "wolf" which, as we all know, doesn't end well.